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02 April 2012

No, Dr. Gupta, hummingbird fuel is not "toxic"

Sugar is toxic? Not this hummingbird's opinion.

Whenever someone asks me whether or not sugar or high-fructose corn syrup is "toxic," I remind them that every few days I make up a simple solution of four parts boiled water and one part plain white table sugar. This I use to fill the hummingbird feeders in my yard here in Arizona and the little guys never complain about it.

In fact, they lap up the sweet nectar -- as much as they can get with their long tongues -- to fuel their high metabolism. Then, they fly off (or get chased off) to their perches and I make a note that most will return within 30 to 45 minutes for more. Research shows their little bodies will have oxidized all the ingested sucrose by that time (1).How can hummingbird fuel be evil? It's just not, as Dr. David Katz pointed out a year ago in a rebuttal to Dr. Lustig's viral YouTube video and Gary Taubes's article in the New York Times Magazine. Another excellent rebuttal was "The bitter truth about fructose alarmism" on Alan Aragon's Blog posted January 2010 in response to Dr. Lustig. The main problem with Dr. Lustig's argument, as pointed out by many scientists, is in its oversimplifications with intent to demonize a single nutrient in a manner that is out of context.

Now, it's happened again on Sunday's 60 Minutes episode "Is sugar toxic?" The oversimplifications presented in the episode are the same as before and sure to just add more to the hysteria surrounding sugar. And, Dr. Gupta's reporting is hardly balanced, using Dr. Lustig to drive the main direction of the episode with only a sugar industry spokesperson to offer a differing opinion.

No, Dr. Gupta, sugar is not toxic. You've said that "almost every scientist" you've talked to agrees that cutting sugar from diet will prevent disease, even cancer. However, most evidence-based nutritionists would agree that sugar itself is not the problem; it's the eating or drinking an excess of anything that makes something toxic -- whether it be carbohydrate, fat, alcohol, or arsenic. Furthermore, to call sugar or high-fructose corn syrup "toxic" or uniquely responsible for driving obesity and disease in the United States is wrong and ignores wider problems of overeating, sedentary lifestyle, and other complex factors.

Sugar is just an easy target, especially high-fructose corn syrup because it was only recently introduced in the 1970s displacing table sugar in many places. Among consumers, there are so many misconceptions about this nutritive sweetener that it has become the scapegoat for every chronic disease. However, it's metabolically the same as table sugar, rightfully noted by Dr. Lustig in the Dr. Gupta's report (2). What was not mentioned was that four years ago the American Society for Nutrition reported that there was no strong correlation between obesity and HFCS availability; even when HFCS availability began dropping in the United States, obesity rates did not (3). Again, the real problems lie in overconsumption of all sources of calories along with sedentary lifestyle.

Yet, the way the segment is presented, sugar is equated to being as addictive as cocaine or tobacco -- and something to be regulated.

It's disappointing that Dr. Gupta couldn't put forward a more balanced report by interviewing a scientist who had a different opinion than Dr. Robert Lustig on sugar and fructose. He would not have had to look far.

Biochemist Richard Feinman, for example, could've reminded Dr. Gupta that while it may be true that the focus on fat gave the food industry license to replace many foods with carbohydrate, it's overconsumption of carbohydrate "across the board" that's contributing calories fueling the obesity epidemic. What comes of demonizing just table sugar or high-fructose corn syrup? It will simply lead folks to eat/drink too much of something else, argues Feinman.

What about fructose being uniquely harmful? Dr. Gupta might've thought to consider the opinions of Drs. Sievenpiper, Russel Souza and David Jenkins of St. Michael's Hospital in Toronto, Ontario. They recently published the findings of three extensive systematic reviews and meta-analyses evaluating the effects of fructose as compared to other sources of carbohydrates in randomized controlled feeding trials in the February issues of Annals of Internal Medicine, the British Journal of Nutrition, and Hypertension (4-6). What did they find? Fructose had no significant effect on body weight or blood pressure as compared to other carbohydrate sources. The fruit sugar in amounts normally obtained from fruit (up to and around 10 grams per meal) also appeared to improve glycemic control -- which could ultimately serve to assist weight management.

That's hardly the "toxic" substance that Dr. Lustig and colleagues make fructose out to be in his commentary in Nature (7). In response to Dr. Lustig's opinion paper, Drs. Sievenpiper, de Souza, and Jenkins, wrote a letter that appeared as "Correspondence" in the 23 February issue of the publication (8):

Robert Lustig and colleagues argue that sugar is “toxic,” focusing on the “deadly effect” of the fructose moiety of sucrose. But they are directing attention away from the problem of general overconsumption.

Guidelines on healthy eating encourage fruit consumption, and fruit and fruit products are the third-largest source of fructose in the US diet.

Our meta-analyses of controlled feeding trials indicate a net metabolic benefit, with no harmful effects, from fructose at a level of intake obtainable from fruit.

Their letter was published alongside that of other commenters, such as clinical nutritionists Christiani Jeyakumar Henry and Viren Ranawana of the Singapore Institute, who remind that sugar overconsumption is really a problem of the developed world, not the developing world (9). And, again, maybe it's that the developing world doesn't have the sedentary lifestyle and other complex factors that are associated with obesity and disease in the United States.

To make a villain out of sugar is just nonsense. Instead, it would make more sense to encourage taking a cue from the hummingbirds and, to stay trim, let amounts of carbohydrate and calories consumed overall depend on how much physical activity (hovering and chasing others off) one does per day.

HFCS and table sugar are not the same at least according to one study that tested commercial beverages. HFCS beverages contains 4-5x the calories of the listed value in the form of oligosaccharides(maltodextrin). http://www.fasebj.org/cgi/content/meeting_abstract/24/1_MeetingAbstracts/562.1

This one found a difference between weight gain between HFCS and sucrose fed rats "The first study showed that male rats given water sweetened with high-fructose corn syrup in addition to a standard diet of rat chow gained much more weight than male rats that received water sweetened with table sugar, or sucrose, in conjunction with the standard diet. The concentration of sugar in the sucrose solution was the same as is found in some commercial soft drinks, while the high-fructose corn syrup solution was half as concentrated as most sodas."http://www.princeton.edu/main/news/archive/S26/91/22K07/

I would also note that the FASEB abstract you present has never been published in a peer reviewed journal. The fact is the method that the abstract used to determine the amount of sugar has not been validated as an appropriate method to determine carbohydrate content; acid hydrolysis has the ability to create small molecules that would be inappropriately identified as sugars. HPLC is the more appropriate method and has been validated and used for several decades.

In regards to the princeton study I guess that's what I get for relying on news articles :)

I don't get how HFCS could be pure glucose/fructose as it's made from starch so it is likely to have at least some degree of long chain sugars in it. I agree that more testing needs to be done though. According to this article almost 1/3 of commercial products with HFCS as first or second ingredient contain mercury so even if the calories are similar that's another reason to avoid it. http://www.medscape.com/viewarticle/587466

I watched Sugar: the Bitter Truth last week. The message I got was NOT that ALL sugar is toxic, but Lustig reiterated several times that the issue was the increase in sugar consumption since the 70s in the form of soda and processed foods. I certainly didn't walk away from it feeling alarmed about eating sugar in its entirety, but I now read the labels of my bread and sauce products to determine how much sugar is added so that I don't exceed recommended daily allowances.

The hummingbird analogy is completely useless, you should know better. Let's make some other comparisons shall we? Vultures eat rotten flesh of days old carcasses and flit off merrily afterwards, so we can eat roadkill? Insects eat off of animals stool, so we can chow down on that now?

Remember, you compared an avian to a mammal so why stop there? Please don't sucker people in with child like analogies, it has no relevance whatsoever to a human metaboloic system or dietary requirements.

Thanks for the plug and I am certainly ready to straighten out Dr. Gupta. Of course, one of the problems is what to do with Drs. Sievenpiper, de Souza, and Jenkins, who worry about the "problem of general overconsumption," calories, calories, calories, and "Guidelines on healthy eating encourage." Have we benefitted from guidelines on "healthy."

There's really only one question which is: Which is more important, the type of carbohydrate, or the replacement of carbohydrate with fat. In terms of an overall strategy, what is the first line of attack? So, as a thought experiment (no subtleties) what is the best big recommendation for general health?

Feinman, your "thought experiment" is essentially a false trichotomy...same thing as a false dichotomy except you've abitrarily limited it to 3 choices rather than 2, when in fact there are many more. This is why you aren't getting answers...because you're committing a common logical fallacy.

It's called Occam's Razor. Or you could think of it as a power series. I'm simply asking: if you could theoretically do only one thing, A or B, which would be better? There are many other choices but in a thought experiment you imagine these to be held constant or to be the higher order terms in a power series. In fact, Krauss's 2006 experiment is really like A. and Stanhope, et al is like B. You can see which makes a bigger difference. Choice D is you don't want to play.

Well, of course, Krieger is right. There's something wrong with the question. My blogpost at http://wp.me/16vK0 discusses the fact that it is no a fallacy so much as it is screwy but it is based on nutrition researchers saying that "the type of carbohydrate is more important than how much carbohydrate" usually having fructose in mind. "more important" is weird because fructose is a carbohydrate. The post shows that, insofar as you can take the question seriously, B. is the better choice. The post does, however, tell you how to reduce fructose.

Gosh - you people seem obsessed with word play - get over the fact that some said sugar was toxic, at the end of the day, just look at your population - OBESE - why?.. well partly or largely due to bad diets, largely containing sugar, plus little exercise. Sure if you want to stay that way keep on eating those sugary donuts, and drinking those sugar filled super sized sodas - or...cut down the sugar content and see the weight drop off - I know - I've done it. And get over those damn hummingbirds as well - thank god the whole population isn't so stupid as to believe such irrelevant analogies!

if sugar is really toxic, then a lot more people would be dead. Even I with my basic education in biology and human physiology know that it's all about the DOSE i.e. Amount ingested.. and in fact the body requires energy.

About Me

I'm a science and health writer based in the Gilbert, Ariz., with a passion for good food combined with a good story. My background is in science communications with a master's of science degree in human nutrition and a bachelor's of arts degree in English. I've written for a variety of publications including Scientific American, Outside Online, the American Society for Nutrition's Nutrition Notes Daily, and the Institute of Food Technologists' Food Technology print magazine. I'm an active member of several respected organizations including the National Association of Science Writers and the American Association for the Advancement of Science. I'm also interested in wildlife conservation and am a member of the National Audubon Society and the American Society of Naturalists.